The invention relates to a rubber hose provided with an outer metal protection, a so-called armouring, and -a vulcanised and/or adhesively bonded coupling, in particular the invention relates to a flexible rubber hose provided with reinforcing plies and a process of producing the same.
It is known that high-pressure flexible pipes and hoses should be often provided with an outer armouring in order to achieve an outer mechanical protection. Therefore, various designs have become known and used all over the world.
Most high-pressure rubber hoses having a relatively large diameter are provided with an adhesively bonded coupling before vulcanisation. Such constructions have been described in the following Hungarian Pat. Nos. 157 310, 168 837, 176 336, 206 404, 207 150, 209 627, and 218 334.
When an outer armouring is required a so-called xe2x80x9copen-profile flexible stripwound metalpipexe2x80x9d is wound on the hose after vulcanisation and fastened at the couplings. A drawback of this method is that the damaged, cracked flexible stripwound metalpipe can wind off easily from the hose and the protection is lost.
According to another known method, a flat steel profile with a circular segment or rectangular cross section is wound on the hose with a small pitch. This operation can be easily carried out but the damaged steel profile unwinds even more easily than the open-profile flexible stripwound metalpipe. A further drawback is that it does not cover the hose surface gap-free, therefore, it does not protect the hose sufficiently from piercing and cutting actions.
The above drawbacks can be eliminated by using an outer stripwound metalpipe with an interlocked profile (xe2x80x9cinterlocked flexible stripwound metalpipexe2x80x9d). This type of flexible stripwound metalpipe has long been known, see, for example, Gumiipari Kxc3xa9zikxc3x6nyv (Rubber Handbook; in Hungarian), TAURUS OMIKK, Vol. II, p. 669. This solution can be easily used if the hose is vulcanised without coupling and then the flexible stripwound metalpipe, which has been cut to size previously, is pulled on the hose and finally the coupling is mounted.
However, if the coupling should be mounted before vulcanising the hose this simple method cannot be used as the outer diameter of the coupling is always significantly larger than that of the hose body, thus, an interlocked flexible stripwound metalpipe fitting tight on the hose body can not be applied after vulcanisation.
It is noted that GB Pat. No. 2 0510297 describes a hose whose outer cover and inner layer are both made from S or Z profiles, however, both the construction of these hoses and the task of the said layers differ from the discussed hose assemblies and from the outer layer providing outer mechanical protection discussed by us. The above hose is not made from rubber, thus, there is no vulcanisation step in its manufacturing process.
Therefore, according to the prior art, an outer interlocked flexible stripwound metalpipe armouring could not have been used when the coupling was mounted before vulcanisation.
Therefore, the object of the invention is to develop an assembly with the application of the said interlocked flexible stripwound metalpipe and a process for the production of the said hoses.
In accordance with the invention it has been discovered that the diameter of an interlocked flexible stripwound metalpipe which is pre-fabricated with the given diameter can be modified by torsion. It is especially easy to change the diameter of the interlocked flexible stripwound metalpipe if relatively shortxe2x80x94a few meters longxe2x80x94sections are used which are spliced on the hose after achieving the required diameter.
Therefore, the main feature of the hose assembly according to the invention, which is provided with an outer metal armouring and a vulcanised and/or adhesively bonded coupling, is that the armouring is constituted by a flexible stripwound metalpipe with an interlocked profile which is spliced at least from two sections and fits with a minimal gap on the hose below.
The main feature of the process according to the invention is that flexible stripwound metalpipes with an interlocked profile, comprising two or more sections, are pulled on the hose, the flexible stripwound metalpipe is subjected to a torsion, thus, the gap between the hose and the flexible stripwound metalpipe is reduced to a minimum, the flexible stripwound metalpipe sections are spliced and the flexible stripwound metalpipe ends are fastened to the hose couplings, if desired.
Preferably, the flexible stripwound metalpipe sections are pulled on an unvulcanised hose body which is provided partially with a rubber cover and also a wrap, if desired, before mounting one or both couplings.
It is also preferable if at least two of the flexible stripwound metalpipe sections have different diameters or a flexible stripwound metalpipe can be deformed by torsion so that the diameters will allow the flexible stripwound metalpipes to slip into each other.
According to a preferable embodiment of the invention, after pulling the flexible stripwound metalpipe sections on the hose, the coupling or couplings are mounted, the rubber cover is applied, a wrap is provided, if desired, and the hose is vulcanised.
The wrap can be first removed from the hose section freed by the overlapping of the flexible stripwound metalpipes and then it is removed gradually from the other parts of the hose by displacing the flexible stripwound metalpipe sections along the hose body.
During a possible application of the process according to the invention, flexible stripwound metalpipe sections having an inner diameter larger than the largest diameter above the coupling are pulled on the finished vulcanised hose.